For now, it’s just a patch and it’s not yet clear if and when it will be part of the official Chrome release. As GHacks explains:

Since there is no way of adding extensions to Chrome yet users have to live with some limitations. Only scripts in c:scripts are loaded and only if the user adds the parameter –enable-greasemonkey by appending it to the program’s shortcut.

The Firefox Greasemonkey extension has been a huge success, and spawned an entire ecosystem of scripts, developers, and users in its own right. Its ultra simplicity has made it immeasurably easier for enthusiasts to “scratch their own back” and patch up a troublesome website in a matter of minutes. It’s not hard to see how the pure Javasript approach could be extended to form a more comprehensive extension platform. It will be interesting to see if, as I speculated on my blog today, this patch is to be the seed for Google’s overall approach to Chrome extensions.

In any event, the Chrome space has a lot of user-scripting innovations to look forward to in coming months. And I daresay the odd porting effort too.

Great news indeed!
I think it would make sense to use the Greasemonkey API as the basis for a user-JS standard to be adopted by all browsers. It is needed and and has the potential to democratize interface. Obviously, we at ShiftSpace have a lot of interest in seeing this happen, and some ideas (and experience) of how it should be implemented.